Jet nozzle



ATTORNEY Nov. 19, 1963 G.A.A1.BE1s ETAI.

JETV NozzLEV Filed July 26, 1960 United States Patent O 3,111,179 .EETNOZZLE Gus A. Albers, Houston, and Edward B. Wiilianis, Jr.,

Greenville, Tex., assignors, by mesue assignments, to

A and B Metal Manufacturing Company, lne., Houston,

Tex., a corporation of Texas Filed .luly 26, 196e, Ser. No. 45,373 4Claims. (Cl. 175-393) lhis invention relates to jet nozzles, `andparticularly those for discharging abrasive uids such las the jetnozzles used in rotary drill bits for `drilling earth formations.

For example, rotary drill bits, of this character, are equipped withdownwardly and sometimes upwardly directed nozzle-like openings fordischarging powerful jets of drilling fluid downwardly between thecutter teeth and onto the 'bottom of the bore hole to remove cuttingsrapidly rand to induce upward flow of drilling fluid for carrying thecuttings to the Vtop of the bore hole. Such powerful jets have been verysuccess-ful in cleaning the teeth of the bit and clearing the bot-tom ofthe hole so that the teeth of the bit are continuously cutting on newformation, thereby greatly increasing the eiciency ot the bit. However,the drilling iluid contains abrasive material, with the result that thesurfaces of the nozzle-like openings are soon eroded.

This diiiiculty has been relieved by constructing the jet nozzles of anextremely hard -and dense -metal or metal alloy that is resistant toerosion by the `abrasive action of the high pressure drilling fluid.Because of vthe dii'lculty of machining such hard material, the jetnozzles are usually of cylindrical shape and have an outer diameter tocontain a `conical cavity necessary to orrn and direct the jets ofdrilling tiuid. Also, due to the difficulty in machining the metal, thejet nozzles are simply inserted within the open ended recesses that areprovided in the body of the drill bit, and `are retained by a lock-ringfitted into `an annular groove that 'is inset within the open end of therecess. Because it is necessary to make the jet nozzle cylindrical, itis obvious that they contain -a `substantial amount of metal and areexpensive. Also, the high pressure fluid acting on the conical surfaceexents such high pressure on the retaining rings that the jet nozzlesare diicul-t to retain in the body of the bit, with the result that thejet nozzles are often pushed out by the pressure into the bottom of thebore hole where they are destructive to the teeth of the bit.

It is therefore the principal object of the present invention to providea jet nozzle of less expensive construction and which, if it becomeslost, is readily disintegrated by the .teeth `of the bit, withoutdamaging the bit.

Another object of the invention is to provide a jet nozzle with an innerthin walled shell of Wear resistant material yand to provide theexterior `shape by an outer breakable casing of inexpensive nonmetallicmaterial such as a synthetic plastic, whereby the jet nozzle may beproduced inexpensively by prcmolding the shell of a tungsten carbidematerial and molding the plastic about the shell.

Another object ofthe invention is to provide ya jet nozzle with atungsten carbide shell having sufficiently high density to withstandabrasion and destruction by chemical action ofthe uids.

further obiect of the invention is to provide an improved jet nozzle forreplacement of conventional jet nozzles.

In accomplishing these and other objects of the invention as hereinafterpointed out, we have provided improved structure, the preferred form yofwhich is illustrated in the accompanying drawings, wherein:

FIG. l is a sectional view through the bottom of a bore 3jr-,l l l,179Patented Nov. 19, 1963 race hole being drilled by `a rotary bit equippedwith jet nozzles embodying the features of the present invention.

FIG. 2 is a 'fragmentary section ,through a portion of the body of thebit and the improved jet nozzle contained therein, ythe section beingtaken on the line 2 2 of FiG. l.

FG. 3 is ya similar section, but showing the parts in disassembled -andin spaced apart relation to .better illustrate the construction.

FIG. 4 is a perspective view of the shell as viewed from the outlet endthereof.

FIG. 5 is `a similar view as viewed from the inlet end thereof.

Referring more in detail to the drawings:

1 designates :a bore hole being `drilled through an earth formation 2 byla drill bit 3 attached to the lower end of a drill pipe 4. The ydrillpipe extends to the top of the bore hole and is rotated in accordancewith the usual practice. The drill bit 3 includes a body 5 that isattached to ythe lower end of the drill pipe and carries cutters 6having cutting teeth 7 that roll upon and chip away the bottom of thebore hole. Circulated under high pressure from the top ot the bore holeis a drilling huid that `discharges through the body of the bit in yoneor more downwardly directed jets 8 that discharge between the teeth ofthe cutters and onto the bottom of Ithe bore hole to clean the teeth 7`and to clear the bottom of the bore hole of cuttings. The `cuttingsyare washed upwardly of the bore hole on :the exterior side of the drillpipe to the upper end thereof, in `accordance with rotary drilling ofbore holes. The bit body may also be provided with one or more upwardlydirected jets 9 to increase the velocity of the upward iiow of thedrilling uid.

As above described, `such `drilling fluid contains abrasives 'and isdestructive to the jet oriiices lo and ll that are provided in the bodyof the bit. This dihiculty has been relieved by providing the body ofthe bit with recesses 12 for containing jet nozzles or inserts in theshape of a cylinder. The cylindrical jet nozzles are completely formedoi extremely hard, highly resistant metal or metal alloy having conicalcavities shaped to provide the jet orifices.

As above described, such cylindrical jet nozzles are dilicult tomanufacture and machine, consequently the machining to retain them iscarried out on the body of the bit. The portions 13 of the body of thebit that contain the iiuid passageways 'i4 are counterbored to providethe recesses l2 and form shoulders l5 against which the inlet ends ofthe jet nozzles abut, and are retained by an expansion ring 16 which isinserted in an annular groove 17 that is inset from the open end 1S ot"the recess l2 as shown in FIG. 2. In order to prevent leak` age of thedrilling uid around the exterior of the cylindrical jet nozzle, therecess 12 is encircled by an annular groove 19 containing a sealingelement such as an O ring 2li.

'In order to provide less expensive and more satisfactory jet nozzles,the present invention contemplates a jet nozzle that replaces thepresent extremely expensive nozzles and which may be retained in a likemanner. The jet nozzles of the present invention are of compositeconstruction in that they include a thin walled inner shell 21 of theexpensive wear resistant material and an outer casing 22 of lessexpensive `and breakable material that is preferably molded about thecircumference of the shell in order to make iirm Contact therewith andassure complete backing and support of the shell.

The wear or abrasion resistant shell 2-1 may be constructed by castingor by sintering, but preferably by molding thereof under heat andpressure. The materials used are preferably granules of tungsten carbideor a like alloy and a suitable bonding metal such a cobalt, nickel 3 orthe like, combined under heat and pressure in a Imold having a cavitycorresponding to the inner and outer contour of the shell. In order toreduce porosity, the grain sizes of the tungsten carbide are regulatedto eliminate as much as possible voids between particles.

The shell 211 has a cylindrical neck portion 23, forming the dischargeorifice of the nozzle, and a generally conical body portion 24 aringfrom the neck portion 23, whereby the base 25 thereof forms the inlet 26t0 the nozzle. The wall thickness of the neck and body portions need beonly enough to withstand application of the casing 22. The shell is,therefore, of minimum weight and contains a minimum amount of the costlymaterial.

In forming the casing, the shell rnay be placed coaxially within acylindrical cavity of a mold (not shown) and the plastic material isextruded into the mold to now around the shell with suicient pressure toassure a rm contact with the surface of the shell and to form a smoothexterior cylindrical surface 2,7 conforming to the cylindrical surface28 of the recess 12. After the molding operation, there is sufficientcohesion between the pfl-astic material and the exterior surface `of theshell to maintain the parts in unitary assembly and assure a solid andfirm backing of the thin walled shell. While we have particularlyspecified a plastic material, other materials may be substituted thatare capable of fiowing around the shell and which are capable of takingon a set without placing the shell under undue stress. It is also essential that a casing material be selected which will maintain tightness ofthe shell therein under different temperature conditions to which thejet nozzles may be subjected.

In inserting a jet nozzle constructed as described, the ring is insertedin the groove 19 and the jet nozzle is inserted in the recess until thebase is in abutment with the shoulder 15. After insertion of the jetnozzle, the expansion ring 16 is contracted to a diameter for movementthrough the open end of the recess 12 until it comes in contact with theend face of the nozzle, whereupon it is lallowed to spring into theannular groove 17 to clock the jet nozzle in position.

With the jet nozzle in place, the drilling uid contacts only theinterior surface of the shell 21. The shell 21 thus resists abrasion bythe abrasive elements in the drilling fluid, so that the jets may bedischarged with sufficient velocity to accomplish the intended purpose.It is obvious that the casing is completely shielded from the erosiveeffects of the drilling liuid by the shell, and `at the same time thecasing provides firm and solid backing for the shell.

Should one or more of the jet nozzles become displaced and lost into thebottom of the hole, the casing being relatively soft and the shellrelatively frangible are readily broken up by the bit without damagingthe teeth 'of the cutters. Any fragments of the jet nozzle areimmediately reduced as -to size vvhere they are easily washed to the topof the hole along with the cuttings.

From the foregoing, it is `obvious that we have provided a jet nozzlecapable of `withstanding the abrasion of high pressure jets with aminimum amount of the costly tungsten carbide material. The jet nozzlesmay therefore 'be supplied at a comparatively low cost. It is alsoobvious that the casing portion thereof adequately backs and supportsthe Ishell portion. If one or more of the jet nozzles are displaced, itis obvious that Ithe composite unit is readily disrupted and disposed ofwithout damaging the teeth of the cutters.

What We claim `and desire to secure by Letters Patent is:

1. A jet nozzle comprising -a thin Walled shell of Wear resistantmaterial and having ran inner surface of a shape to provide a dischargeorice and a generally conical inlet converging into said dischargeorifice and having an exterior surface conforming in shape to said innersurface for providing a thin wear resistant wall of substantiallyuniform thickness, and a plastic casing providing a solid and rm backingsurrounding the periphery of the shell and having an inner surface incohesive contact with the `entire outer surface of the shell and havinga generally cylindrical outer periphery.

2. A jet nozzle for drilll bi-ts and the like, said jet nozzlecomprising a thin walled shell of wear resistant material composed of analloy principally of tungsten carbide granules and a bonding metal andhavin-g an inner surface of a shape =to provide an annular dischargeorifice and a generally conical inlet converging into said annulardischarge orifice and having an exterior surface conforming in shape tothe inner surface to provide a thin Wear resistant Wall of substantiallyuniform thickness, and a plastic casing providing a solid and firmbacking surrounding the periphery of the shell and having an innersurface in cohesive contact with the entire outer surface to firmlysupport said shell when the jet nozzle is mounted within a drill bit andhaving a generally cylindrical outer periphery, said plastic casinghaving the property of disintegrating with the shell in case the nozzleshould become dislodged from the drill blt.

3. A jet nozzle comprising 4a thin iwalled shell of wear resistantmaterial composed of an :alloy principally of tungsten carbide granulescombined with a bonding metal and having an inner surface of la shape toprovide a discharge orifice and a generally conical inlet converginginto said discharge orifice and having an exterior surface conforming inshape to the inner surface to provide la thin wear resistant wall ofsubstantially uniform thickness, and a breakable nonmetallic casingproviding a iirm backing surrounding the periphery of the shell andhaving an inner -surface in cohesive contact with the entire outersurface `of the shell and having Ia generally cylindrical outerperiphery, said inner shell being frangible upon breaking apart of thecasing.

4. In a drill bit having a Channel for passing 'drilling fluid to thecutting elements of the drill bit and having a cylindricalcounter-recess -at the discharge end thereof and forming an annularshoulder encircling the channel, a jet nozzle in said recess comprisinga thin walled shell of wear resistant material composed of an alloyprincipally of tungsten carbide granules combined with a bonding metaland having yan inner surface `of a shape to provide a discharge orificeand a generally conical Iinlet end abutting said shoulder convergingtherefrom into said discharge orifice and having an exterior surfaceconforming in shape to the inner surface to provide a ,thin wearresistant wall yof substantially uniform thickness, and a breakableplastic casing providing a firm and solid backing surrounding theperiphery of the lshell and having an inner surface in cohesive contactwith the entire outer surface -o-f the shell and having a generallycylindrical outer periphery hitting the counterbore and protected by theshell from ythe erosive effects of the drilling uid, said inner :shellbeing frangible upon breaking apart of the plastic casing by saidcutting elements of the bit upon accidental Idisplacement of the jetnozzle from said recess when lthe bit is in use.

References Cited in the le of this patent UNITED STATES PATENTS

1. A JET NOZZLE COMPRISING A THIN WALLED SHELL OF WEAR RESISTANTMATERIAL AND HAVING AN INNER SURFACE OF A SHAPE TO PROVIDE A DISCHARGEORIFICE AND A GENERALLY CONICAL INLET CONVERGING INTO SAID DISCHARGEORIFICE AND HAVING AN EXTERIOR SURFACE CONFORMING IN SHAPE TO SAID INNERSURFACE FOR PROVIDING A THIN WEAR RESISTANT WALL OF SUBSTANTIALLYUNIFORM THICKNESS, AND A PLASTIC CASING PROVIDING A SOLID AND FIRMBACKING SURROUNDING THE PERIPHERY OF THE SHELL AND HAVING AN INNERSURFACE IN COHESIVE CONTACT WITH THE ENTIRE OUTER SURFACE OF THE SHELLAND HAVING A GENERALLY CYLINDRICAL OUTER PERIPHERY.